1. Field of the Invention
This invention relates to interferometers and more particularly to Fourier transform interferometers having a rotary refractive window.
2. Description of the Related Art
One of the most common arrangements for performing the interferometric function is known as the Michelson Configuration which uses light interference in spectroscopy where two beams of light with separate optical paths are directed toward a common point forming interference fringes.
Dybwad, U.S. Pat. No. 4,654,530, issued Mar. 31, 1987, titled Refractively Scanned Interferometer discloses a window 30 which refractively changes the path length of a light beam. The window is rectangular which produces 4 spectrum scans per rotation.
Further Dybwad uses two arms of the interferometer traveling through the window for additively changing the path length of the light beams and compensating for non-linearities occurring in the window.